(CN) — It turns out any old red brick could be a power brick, according to new research from chemists who’ve devised a coating that can turn red bricks into blue batteries.
“We have taken a typical brick you use for constructing houses — we actually went to the hardware store, that’s where we bought them, there’s nothing special about them — we brought them back into the lab, and we started doing chemical synthesis on the bricks,” Julio D’Arcy, assistant professor of chemistry at Washington University in St. Louis, said in an interview. “My lab employees are really interested in using materials like rust, like iron corrosion … as our reactant in chemical synthesis.”
Bricks owe their red pigmentation to iron oxide, better known as rust, and this latent chemical composition was the basis for D’Arcy’s lab’s method.
“We ended up synthesizing, on the bricks, a polymer that conducts electricity and stores energy. The way that we did that was very simple: fill up the bricks with acid,” he said. Those acids infiltrate the pores and convert this iron oxide in the brick into a chemical reactant that’s actually very useful for the synthesis of plastic.”
D’Arcy and his colleagues placed a brick in an oven and pumped acid vapors in, dissolving the iron oxide at a molecular scale.
“The second step is to flow a second gas to the brick, and that second gas is monomer vapor,” the professor said.
The two reactant gases flow consecutively into the oven, and the process is complete.
“Once you open that oven, and the chemical reaction is done, the brick comes out of the oven and it’s no longer red in color, but it’s blue in color. So we know, whenever we see a blue color, that we have made one of our polymers,” D’Arcy said. “The paper demonstrates that it is stable, and it is reproducible, and all you have to do is just a one-step reaction, where you introduce two gases into the brick, you heat up the brick, and you make a polymer.”
That blue polymer, whose nanofibers penetrate the porous interior of the brick, acts as a kind of “ion sponge” that stores and conducts electricity.
In their study, published Tuesday in Nature Communications, the scientists powered a green LED light from just one brick. And more bricks means more energy storage — the group boasts that just 50 bricks connected to solar cells could power emergency lighting for five hours.
“You can just increase the number of bricks and you can increase the amount of energy that’s stored. However, it’s not a very good strategy,” D’Arcy said. “The more bricks you coat, the more expensive it is. A better alternative is not to scale up, but to make the bricks the best possible energy storage units you can.”
So rather than heading to the hardware store, the researchers are making their own bricks.
“You want to be able to beat AA batteries or AAA batteries, because then you could actually create jobs, you could actually start a company,” D’Arcy said. “What we need to do is to find funding in order for us to develop new bricks. … The bricks that we make are not like the bricks we used for this publication, we’re actually using bricks that have other metals in them, that can increase the amount of energy that could be stored.”
D’Arcy says the bricks can be recharged about 10,000 times, and each recharge can happen in 13 minutes.
“That’s only possible because the polymer that we made allows it,” he said.
Technically speaking, the converted bricks aren’t batteries, but supercapacitors — a conducting material with lower energy density than a battery, but which charges and discharges much more quickly.
And though existing infrastructure could be converted into blue-brick energy storage units, D’Arcy warns that more efficient solutions will require the special-made bricks his lab is working on.
“We can grab a wall that’s already assembled, and we can retroactively convert it into one of our energy storage units. But there are problems. One, you have to bring the equipment with you, and that costs you more. Two, whenever we build devices, you always need wires,” he said. “It wouldn’t look as pretty, you would have to dig into the wall, you would have to put the wires there somewhere, you would have to connect them to a solar cell.”
D’Arcy hopes his group’s findings will integrate with smart home technology, architecture and other environmentally mindful developments.
“Bricks are an environmental substrate,” D’Arcy said. “Our technology is a green technology that complements solar cells.”